import java.time.LocalDateTime;
import java.util.concurrent.TimeUnit;

public class ThreadTimeUnit {
    public static void main(String[] args) throws InterruptedException {
        System.out.println("主线程开始执行:"+ LocalDateTime.now());
        TimeUnit.SECONDS.sleep(3);
        System.out.println("主线程开始执行:"+LocalDateTime.now());
    }
}
